The invention relates to an auxiliary power supply for a vehicle with a combustion engine, and to a method for operating the same.
Many vehicles, including for example trucks, buses and premium segment cars, have a need for electric power during periods when the vehicle""s combustion engine is turned off and at a standstill, for supplying auxiliary drives or other electronic equipment, such as air-conditioning, cooking, and telecommunication. These functions are currently unavailable in vehicles, e.g., while parked. When the engine is off, some vehicles run a generator driven by a small internal combustion engine; others idle their combustion engines causing substantial fuel consumption due to part load conditions for the diesel engine and significant emissions of pollutants and noise.
Fuel cell vehicles, on the other hand, have the ability to produce electric power during stand-still of the vehicle, without causing considerable pollution or noise compared to vehicles with a combustion engine. U.S. Pat. No. 4,657,829 A1 discloses a fuel cell car with a fuel cell vehicular power plant. Fuel for the fuel cell stack is supplied by a hydrocarbon catalytic cracking reactor and CO shift reactor. A water electrolysis subsystem is associated with the stack. During low power operation, part of the fuel cell power is used to electrolyze water with hydrogen and oxygen electrolysis products being stored in pressure vessels. During peak power intervals (viz, during acceleration or start-up), pure oxygen and pure hydrogen from the pressure vessels are supplied as the reaction gases to the cathodes and anodes of the fuel cell stack in place of air and hydrocarbon reformate. However, for a standard vehicle with a combustion engine there is no energy production solution with a fuel cell power unit.
One object of the invention is to provide an electric power supply for a vehicle with a combustion engine, which can supply power even at stand-still of the combustion engine.
Another object of the invention is to provide a vehicle power supply that reduces pollution and noise.
Still another object of the invention is to provide a method for operating such a power supply.
These and other objects and advantages are achieved by the power supply method and apparatus according to the invention in which the fuel cell system operates at least indirectly on vehicle based fuels. That is, vehicle produced electric power is used to electrolyze water while the vehicle 1 is operative, and this hydrogen is then used when the vehicle 1 is inoperative to generate electric power via a fuel cell.
According to the invention there is no need to run a combustion engine for producing electric power while the vehicle engine is off; and it is unnecessary to tank an additional fuel and store it on board of the vehicle to operate the fuel cell.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.